1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 *  FPU support code, moved here from head.S so that it can be used
4 *  by chips which use other head-whatever.S files.
5 *
6 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
7 *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
8 *    Copyright (C) 1996 Paul Mackerras.
9 *    Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
10 */
11
12#include <linux/export.h>
13#include <asm/reg.h>
14#include <asm/page.h>
15#include <asm/mmu.h>
16#include <asm/cputable.h>
17#include <asm/cache.h>
18#include <asm/thread_info.h>
19#include <asm/ppc_asm.h>
20#include <asm/asm-offsets.h>
21#include <asm/ptrace.h>
22#include <asm/asm-compat.h>
23#include <asm/feature-fixups.h>
24
25#ifdef CONFIG_VSX
26#define __REST_1FPVSR(n,c,base)						\
27BEGIN_FTR_SECTION							\
28	b	2f;							\
29END_FTR_SECTION_IFSET(CPU_FTR_VSX);					\
30	REST_FPR(n,base);						\
31	b	3f;							\
322:	REST_VSR(n,c,base);						\
333:
34
35#define __REST_32FPVSRS(n,c,base)					\
36BEGIN_FTR_SECTION							\
37	b	2f;							\
38END_FTR_SECTION_IFSET(CPU_FTR_VSX);					\
39	REST_32FPRS(n,base);						\
40	b	3f;							\
412:	REST_32VSRS(n,c,base);						\
423:
43
44#define __SAVE_32FPVSRS(n,c,base)					\
45BEGIN_FTR_SECTION							\
46	b	2f;							\
47END_FTR_SECTION_IFSET(CPU_FTR_VSX);					\
48	SAVE_32FPRS(n,base);						\
49	b	3f;							\
502:	SAVE_32VSRS(n,c,base);						\
513:
52#else
53#define __REST_1FPVSR(n,b,base)		REST_FPR(n, base)
54#define __REST_32FPVSRS(n,b,base)	REST_32FPRS(n, base)
55#define __SAVE_32FPVSRS(n,b,base)	SAVE_32FPRS(n, base)
56#endif
57#define REST_1FPVSR(n,c,base)   __REST_1FPVSR(n,__REG_##c,__REG_##base)
58#define REST_32FPVSRS(n,c,base) __REST_32FPVSRS(n,__REG_##c,__REG_##base)
59#define SAVE_32FPVSRS(n,c,base) __SAVE_32FPVSRS(n,__REG_##c,__REG_##base)
60
61/*
62 * Load state from memory into FP registers including FPSCR.
63 * Assumes the caller has enabled FP in the MSR.
64 */
65_GLOBAL(load_fp_state)
66	lfd	fr0,FPSTATE_FPSCR(r3)
67	MTFSF_L(fr0)
68	REST_32FPVSRS(0, R4, R3)
69	blr
70EXPORT_SYMBOL(load_fp_state)
71_ASM_NOKPROBE_SYMBOL(load_fp_state); /* used by restore_math */
72
73/*
74 * Store FP state into memory, including FPSCR
75 * Assumes the caller has enabled FP in the MSR.
76 */
77_GLOBAL(store_fp_state)
78	SAVE_32FPVSRS(0, R4, R3)
79	mffs	fr0
80	stfd	fr0,FPSTATE_FPSCR(r3)
81	REST_1FPVSR(0, R4, R3)
82	blr
83EXPORT_SYMBOL(store_fp_state)
84
85/*
86 * This task wants to use the FPU now.
87 * On UP, disable FP for the task which had the FPU previously,
88 * and save its floating-point registers in its thread_struct.
89 * Load up this task's FP registers from its thread_struct,
90 * enable the FPU for the current task and return to the task.
91 * Note that on 32-bit this can only use registers that will be
92 * restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
93 */
94_GLOBAL(load_up_fpu)
95	mfmsr	r5
96#ifdef CONFIG_PPC_BOOK3S_64
97	/* interrupt doesn't set MSR[RI] and HPT can fault on current access */
98	ori	r5,r5,MSR_FP|MSR_RI
99#else
100	ori	r5,r5,MSR_FP
101#endif
102#ifdef CONFIG_VSX
103BEGIN_FTR_SECTION
104	oris	r5,r5,MSR_VSX@h
105END_FTR_SECTION_IFSET(CPU_FTR_VSX)
106#endif
107	MTMSRD(r5)			/* enable use of fpu now */
108	isync
109	/* enable use of FP after return */
110#ifdef CONFIG_PPC32
111	addi	r5,r2,THREAD
112	lwz	r4,THREAD_FPEXC_MODE(r5)
113	ori	r9,r9,MSR_FP		/* enable FP for current */
114	or	r9,r9,r4
115#else
116	ld	r4,PACACURRENT(r13)
117	addi	r5,r4,THREAD		/* Get THREAD */
118	lwz	r4,THREAD_FPEXC_MODE(r5)
119	ori	r12,r12,MSR_FP
120	or	r12,r12,r4
121	std	r12,_MSR(r1)
122#ifdef CONFIG_PPC_BOOK3S_64
123	li	r4,0
124	stb	r4,PACASRR_VALID(r13)
125#endif
126#endif
127	li	r4,1
128	stb	r4,THREAD_LOAD_FP(r5)
129	addi	r10,r5,THREAD_FPSTATE
130	lfd	fr0,FPSTATE_FPSCR(r10)
131	MTFSF_L(fr0)
132	REST_32FPVSRS(0, R4, R10)
133	/* restore registers and return */
134	/* we haven't used ctr or xer or lr */
135	blr
136_ASM_NOKPROBE_SYMBOL(load_up_fpu)
137
138/*
139 * save_fpu(tsk)
140 * Save the floating-point registers in its thread_struct.
141 * Enables the FPU for use in the kernel on return.
142 */
143_GLOBAL(save_fpu)
144	addi	r3,r3,THREAD	        /* want THREAD of task */
145	PPC_LL	r6,THREAD_FPSAVEAREA(r3)
146	PPC_LL	r5,PT_REGS(r3)
147	PPC_LCMPI	0,r6,0
148	bne	2f
149	addi	r6,r3,THREAD_FPSTATE
1502:	SAVE_32FPVSRS(0, R4, R6)
151	mffs	fr0
152	stfd	fr0,FPSTATE_FPSCR(r6)
153	REST_1FPVSR(0, R4, R6)
154	blr
155